Multiple Sclerosis

Multiple sclerosis is the most common neurological disorder among adults involving central nervous system dysfunction. Inflammation is believed to be a key factor in the pathophysiology of this debilitating, degenerative condition. Although symptoms vary, people with multiple sclerosis may experience fatigue, blurred vision, numbness, loss of balance, difficulty walking and paralysis. There is no cure.

Many of the symptoms of multiple sclerosis can be traced to a process known as demyelination – destruction of the protective myelin sheath that surrounds nerve fibers in the brain and spinal cord. Inflammation and loss of myelin causes disruption to nerve transmission and affects many functions of the body. In multiple sclerosis, immune cells migrate through the blood-brain barrier into the brain leading to inflammation and destruction of the myelin sheath, which insulates the nerves and eventual nerve cell death.

When myelin is healthy and functioning properly, uninterrupted nerve impulses facilitate coordination of mind and body. However, the central nervous system has a limited capacity to repair damaged areas of demyelination, and repeated inflammatory attack often leads to scarring and loss of nerve cells. The inflammatory events that result in demyelination appear clinically as exacerbations or relapses.

The onset of multiple sclerosis may be subtle or dramatic, with isolated or multi-focal symptoms, typically involving the optic nerve, spinal cord or brainstem. The patients in which such an event occurs are at high risk of recurrent clinical attacks, and may be candidates for early disease-modifying therapy.

During episodes of inflammation and clinical relapse, messages from the brain become distorted, triggering the visible signs and symptoms of multiple sclerosis, such as visual changes, loss of coordination, weakness and sensory symptoms. Over time, successive events of demyelination lead to the more severe and persistent manifestations of the disease, including loss of mobility, difficulty with bladder or bowel control, pain, cognitive dysfunction and mood disturbance.

Statistics

According to the National Multiple Sclerosis Society, about 200 Americans are diagnosed with multiple sclerosis every week, affecting approximately 400,000 people nationwide. Patients are usually diagnosed between the ages of 20 and 50. Multiple sclerosis is two to three times more common in women than in men.

In the United States, multiple sclerosis occurs more frequently in the northern states than in southern states. Studies from the early 1990s also found that roughly 95 percent of people with multiple sclerosis were Caucasian, 5 percent were African-American and less than 1 percent were Hispanic. The estimated number of patients range from 1 million to 2.5 million, with highest rates in regions of the world with cooler climates or those regions farthest from the equator. Northern Europe, North America, and parts of Australia and New Zealand have the highest prevalence rates.

Symptoms

Symptoms vary from person to person and include weakness or fatigue; numbness or tingling; blurred vision, impaired color perception or visual loss; poor coordination of muscle movements; difficulty with bladder or bowel control; muscle stiffness (spasticity); speech problems and challenges with memory or other thinking skills.

How is the disease classified?

The natural course of multiple sclerosis is unpredictable. Some people are minimally affected by the disease while others experience rapid progress to total disability.

Relapsing-remitting – characterized by exacerbations followed by periods of complete or incomplete recovery. Incomplete recovery can lead to step-wise accumulation of disability over time in the majority of these patients. In the initial stages of the disease, about 80-90% of individuals with MS have relapsing disease.

Secondary progressive – refers to a stage of the disease where gradual neurological deterioration occurs with or without superimposed relapses. This phase of the disease is always preceded by an initial relapsing-remitting disease course. Approximately 50% of those with relapsing-remitting MS will enter the secondary progressive phase of the disease within 10 to 15 years of the disease onset.

Primary progressive – characterized by a steady progression of disability with few or no exacerbations. Approximately 10% of individuals present with primary progressive disease.

Progressive relapsing – characterized by progressive MS from the onset with infrequent, superimposed relapses. It is an uncommon form of the disease (<5%).
[Source: National Multiple Sclerosis Society]

Other Resources

National MS Society is a national society with local chapters that promote research and provide services, education and advocacy for people with multiple sclerosis and their families.

Medline Plus Health Topics will direct you to information to help answer health questions. MedlinePlus brings together authoritative information from NLM, the National Institutes of Health (NIH), and other government agencies and health-related organizations.

MS ActiveSource® MS ActiveSource is one of the largest MS resources on the Internet.